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Related papers: Infinity thick quasiconvexity and applications

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In an attempt to develop higher-dimensional quasiconformal mappings on metric measure spaces with curvature conditions, i.e. from Ahlfors to Alexsandrov, we show that a non-collapsed $\mathrm{RCD}(0,n)$ space ($n\geq2$) with Euclidean…

Metric Geometry · Mathematics 2023-02-24 Jialong Deng

We study extensions of sets and functions in general metric measure spaces. We show that an open set has the strong BV extension property if and only if it has the strong extension property for sets of finite perimeter. We also prove…

Metric Geometry · Mathematics 2023-02-21 Emanuele Caputo , Jesse Koivu , Tapio Rajala

In this article, for an optimal range of the smoothness parameter $s$ that depends (quantitatively) on the geometric makeup of the underlying space, the authors identify purely measure theoretic conditions that fully characterize embedding…

Functional Analysis · Mathematics 2022-02-16 Ryan Alvarado , Dachun Yang , Wen Yuan

Given a Riemannian manifold M and a hypersurface H in M, it is well known that infinitesimal convexity on a neighborhood of a point in H implies local convexity. We show in this note that the same result holds in a semi-Riemannian manifold.…

Differential Geometry · Mathematics 2016-03-15 Erasmo Caponio

We investigate the first-order differential calculus over extended metric-topological measure spaces. The latter are quartets $\mathbb X=(X,\tau,{\sf d},\mathfrak m)$, given by an extended metric space $(X,{\sf d})$ together with a weaker…

Functional Analysis · Mathematics 2025-03-05 Enrico Pasqualetto , Janne Taipalus

In a complete metric space equipped with a doubling measure and supporting a $(1,1)$-Poincar\'e inequality, we show that every set satisfying a suitable capacitary density condition is removable for Newton-Sobolev functions.

Metric Geometry · Mathematics 2022-11-03 Panu Lahti

We study metric spheres Z obtained by gluing two hemispheres of the Euclidean sphere along an orientation-preserving homeomorphism mapping the equator onto itself, where the distance on Z is the canonical distance that is locally isometric…

Complex Variables · Mathematics 2021-06-03 Toni Ikonen

We prove that for all integers $2\leq m\leq d-1$, there exists doubling measures on $\mathbb{R}^d$ with full support that are $m$-rectifiable and purely $(m-1)$-unrectifiable in the sense of Federer (i.e. without assuming…

Metric Geometry · Mathematics 2025-05-09 Matthew Badger , Raanan Schul

This is the second of two works concerning the Sobolev calculus on metric measure spaces and its applications. In this work, we focus on several approaches to vector calculus in the non-smooth setting of complete and separable metric spaces…

Functional Analysis · Mathematics 2025-10-15 Luigi Ambrosio , Toni Ikonen , Danka Lučić , Enrico Pasqualetto

We study the Lipschitz metric on Teichmuller space (defined by Thurston) and compare it with the Teichmuller metric. We show that in the thin part of Teichmuller space the Lipschitz metric is approximated up to bounded additive distortion…

Geometric Topology · Mathematics 2007-05-23 Young-Eun Choi , Kasra Rafi

We give a new characterization of (homogeneous) Triebel-Lizorkin spaces $\dot{\mathcal F}^{s}_{p,q}(Z)$ in the smoothness range $0 < s < 1$ for a fairly general class of metric measure spaces $Z$. The characterization uses Gromov hyperbolic…

Classical Analysis and ODEs · Mathematics 2016-08-15 Mario Bonk , Eero Saksman , Tomás Soto

We establish a new characterization of the homogeneous Besov spaces $\dot{\mathcal B}^{s}_{p,q}(Z)$ with smoothness $s \in (0,1)$ in the setting of doubling metric measure spaces $(Z,d,\mu)$. The characterization is given in terms of a…

Classical Analysis and ODEs · Mathematics 2016-06-28 Tomás Soto

The property of measure concentration is that an arbitrary 1-Lipschitz function $f:X\to \mathbb{R}$ on an mm-space $X$ is almost close to a constant function. In this paper, we prove that if such a concentration phenomenon arise, then any…

Metric Geometry · Mathematics 2007-05-23 Kei Funano

We give several characterizations of parabolic (quasisuper)- minimizers in a metric measure space equipped with a doubling measure and supporting a Poincar\'e inequality. We also prove a version of comparison principle for super- and…

Analysis of PDEs · Mathematics 2013-01-17 Juha Kinnunen , Mathias Masson

A homemorphism between domains in $\mathbb R^n$, $n\ge 2$ is quasiconformal, with its intricate analytic and geometric consequences, if the (pointwise) linear dilatation -- a purely metric quantity -- is uniformly bounded. Gehring proved…

Functional Analysis · Mathematics 2026-04-01 Behnam Esmayli , Pekka Koskela , Khanh Nguyen

We investigate typical properties of nonexpansive mappings on unbounded complete hyperbolic metric spaces. For two families of metrics of uniform convergence on bounded sets, we show that the typical nonexpansive mapping is a Rakotch…

Functional Analysis · Mathematics 2023-03-21 Christian Bargetz , Simeon Reich , Daylen Thimm

We prove a Leibniz rule for BV functions in a complete metric space that is equipped with a doubling measure and supports a Poincar\'e inequality. Unlike in previous versions of the rule, we do not assume the functions to be locally…

Metric Geometry · Mathematics 2018-11-20 Panu Lahti

This paper aims to study the dual of an extended locally convex space. In particular, we study the weak and weak* topologies as well as the topology of uniform convergence on bounded subsets of an extended locally convex space. As an…

Functional Analysis · Mathematics 2023-01-10 Akshay Kumar , Varun Jindal

Let (X, d) be a quasi-convex, complete and separable metric space with reference probability measure m. We prove that the set of of real valued Lipschitz function with non zero point-wise Lipschitz constant m-almost everywhere is residual,…

Analysis of PDEs · Mathematics 2013-06-21 Fabio Cavalletti

Let $(X,\mathbf{q},\mu)$ be an ultra-RD-space with upper dimension $n\in(0,\infty)$; i.e., it is a quasi-ultrametric space of homogeneous type whose measure $\mu$ satisfies an additional reverse doubling property. Let…

Functional Analysis · Mathematics 2026-04-06 Chenfeng Zhu , Ryan Alvarado , Xianjie Yan , Dachun Yang , Wen Yuan